Perhaps, but remember that many of those who have been infected were asymptomatic or mildly symptomatic, leading them to dismiss their symptoms. Given that these people would have no idea that they were infected, they would be just as inclined as the rest of us to get vaccinated.

> does this mean we only need to vaccinate about 50% of the US population to reach herd immunity?

It depends on the efficacy of the vaccine and the transmission rate, but the numbers can be higher than 90% vaccination rate to achieve heard immunity.

There's a breakdown of the math behind determining this here:

https://www.reddit.com/r/askscience/comments/k9tcv1/if_23_of...